上篇文章，我们编译了go-ethereum的源代码，大家体验了一下开发环境，使用了开发工具，我们从这章开始，进入ETH的学习阶段。我会在每章完成后，给大家提出一些思考。帮助大家。
1、搭建前准备

如果是使用虚拟机上安装的 Ubuntu。请在虚拟机中打开终端，安装SSH。

命令如下：

sudo apt-get install ssh

Windows上，安装 SSH终端工具MobaXterm Professional Edition，自己安装。MAC系统，自带远程工具，或者选择自己喜欢的远程工具如putty或者其他。
编辑器 Visual Studio Code ，可以安装在windows环境下或者MAC下。如果想通过Visual Studio Code操作ubuntu下的文件，请在Visual Studio Code安装拓展插件。
点击左侧状态栏”扩展“　输入　Remote Development　点击安装，安装后，会有文档，详细介绍如何连接远程主机，及操作文件。如下图：

Ubuntu下安装命令
上篇文章，我们通过编译源代码的方式，自己编译了geth客户端，如果仅仅是使用ETH网络，我们可以只安装ETH客户端即可。根据自己场景需要决定。
命令如下：

sudo apt-get install software-properties-common
sudo add-apt-repository -y ppa:ethereum/ethereum
sudo add-apt-repository -y ppa:ethereum/ethereum-dev
sudo apt-get update
sudo apt-get install ethereum

安装测试
安装好后，我们输入如下命令：

geth -h 

显示如下：

NAME:
   geth - the go-ethereum command line interface

   Copyright 2013-2019 The go-ethereum Authors

USAGE:
   geth [options] command [command options] [arguments...]

VERSION:
   1.9.19-stable-3e064192

COMMANDS:
   account                            Manage accounts
   attach                             Start an interactive JavaScript environment (connect to node)
   console                            Start an interactive JavaScript environment
   copydb                             Create a local chain from a target chaindata folder
   dump                               Dump a specific block from storage
   dumpconfig                         Show configuration values
   dumpgenesis                        Dumps genesis block JSON configuration to stdout
   export                             Export blockchain into file
   export-preimages                   Export the preimage database into an RLP stream
   import                             Import a blockchain file
   import-preimages                   Import the preimage database from an RLP stream
   init                               Bootstrap and initialize a new genesis block
   inspect                            Inspect the storage size for each type of data in the database
   js                                 Execute the specified JavaScript files
   license                            Display license information
   makecache                          Generate ethash verification cache (for testing)
   makedag                            Generate ethash mining DAG (for testing)
   removedb                           Remove blockchain and state databases
   retesteth                          Launches geth in retesteth mode
   show-deprecated-flags              Show flags that have been deprecated
   version                            Print version numbers
   wallet                             Manage Ethereum presale wallets
   help, h                            Shows a list of commands or help for one command

ETHEREUM OPTIONS:
  --config value                      TOML configuration file
  --datadir value                     Data directory for the databases and keystore (default: "/home/cuijb/.ethereum")
  --datadir.ancient value             Data directory for ancient chain segments (default = inside chaindata)
  --keystore value                    Directory for the keystore (default = inside the datadir)
  --nousb                             Disables monitoring for and managing USB hardware wallets
  --pcscdpath value                   Path to the smartcard daemon (pcscd) socket file (default: "/run/pcscd/pcscd.comm")
  --networkid value                   Network identifier (integer, 1=Frontier, 3=Ropsten, 4=Rinkeby, 5=Görli) (default: 1)
  --goerli                            Görli network: pre-configured proof-of-authority test network
  --rinkeby                           Rinkeby network: pre-configured proof-of-authority test network
  --yolov1                            YOLOv1 network: pre-configured proof-of-authority shortlived test network.
  --ropsten                           Ropsten network: pre-configured proof-of-work test network
  --syncmode value                    Blockchain sync mode ("fast", "full", or "light") (default: fast)
  --exitwhensynced                    Exits after block synchronisation completes
  --gcmode value                      Blockchain garbage collection mode ("full", "archive") (default: "full")
  --txlookuplimit value               Number of recent blocks to maintain transactions index by-hash for (default = index all blocks) (default: 0)
  --ethstats value                    Reporting URL of a ethstats service (nodename:secret@host:port)
  --identity value                    Custom node name
  --lightkdf                          Reduce key-derivation RAM & CPU usage at some expense of KDF strength
  --whitelist value                   Comma separated block number-to-hash mappings to enforce (<number>=<hash>)

LIGHT CLIENT OPTIONS:
  --light.serve value                 Maximum percentage of time allowed for serving LES requests (multi-threaded processing allows values over 100) (default: 0)
  --light.ingress value               Incoming bandwidth limit for serving light clients (kilobytes/sec, 0 = unlimited) (default: 0)
  --light.egress value                Outgoing bandwidth limit for serving light clients (kilobytes/sec, 0 = unlimited) (default: 0)
  --light.maxpeers value              Maximum number of light clients to serve, or light servers to attach to (default: 100)
  --ulc.servers value                 List of trusted ultra-light servers
  --ulc.fraction value                Minimum % of trusted ultra-light servers required to announce a new head (default: 75)
  --ulc.onlyannounce                  Ultra light server sends announcements only
  --light.nopruning                   Disable ancient light chain data pruning

DEVELOPER CHAIN OPTIONS:
  --dev                               Ephemeral proof-of-authority network with a pre-funded developer account, mining enabled
  --dev.period value                  Block period to use in developer mode (0 = mine only if transaction pending) (default: 0)

ETHASH OPTIONS:
  --ethash.cachedir value             Directory to store the ethash verification caches (default = inside the datadir)
  --ethash.cachesinmem value          Number of recent ethash caches to keep in memory (16MB each) (default: 2)
  --ethash.cachesondisk value         Number of recent ethash caches to keep on disk (16MB each) (default: 3)
  --ethash.cacheslockmmap             Lock memory maps of recent ethash caches
  --ethash.dagdir value               Directory to store the ethash mining DAGs (default: "/home/cuijb/.ethash")
  --ethash.dagsinmem value            Number of recent ethash mining DAGs to keep in memory (1+GB each) (default: 1)
  --ethash.dagsondisk value           Number of recent ethash mining DAGs to keep on disk (1+GB each) (default: 2)
  --ethash.dagslockmmap               Lock memory maps for recent ethash mining DAGs

TRANSACTION POOL OPTIONS:
  --txpool.locals value               Comma separated accounts to treat as locals (no flush, priority inclusion)
  --txpool.nolocals                   Disables price exemptions for locally submitted transactions
  --txpool.journal value              Disk journal for local transaction to survive node restarts (default: "transactions.rlp")
  --txpool.rejournal value            Time interval to regenerate the local transaction journal (default: 1h0m0s)
  --txpool.pricelimit value           Minimum gas price limit to enforce for acceptance into the pool (default: 1)
  --txpool.pricebump value            Price bump percentage to replace an already existing transaction (default: 10)
  --txpool.accountslots value         Minimum number of executable transaction slots guaranteed per account (default: 16)
  --txpool.globalslots value          Maximum number of executable transaction slots for all accounts (default: 4096)
  --txpool.accountqueue value         Maximum number of non-executable transaction slots permitted per account (default: 64)
  --txpool.globalqueue value          Maximum number of non-executable transaction slots for all accounts (default: 1024)
  --txpool.lifetime value             Maximum amount of time non-executable transaction are queued (default: 3h0m0s)

PERFORMANCE TUNING OPTIONS:
  --cache value                       Megabytes of memory allocated to internal caching (default = 4096 mainnet full node, 128 light mode) (default: 1024)
  --cache.database value              Percentage of cache memory allowance to use for database io (default: 50)
  --cache.trie value                  Percentage of cache memory allowance to use for trie caching (default = 15% full mode, 30% archive mode) (default: 15)
  --cache.trie.journal value          Disk journal directory for trie cache to survive node restarts (default: "triecache")
  --cache.trie.rejournal value        Time interval to regenerate the trie cache journal (default: 1h0m0s)
  --cache.gc value                    Percentage of cache memory allowance to use for trie pruning (default = 25% full mode, 0% archive mode) (default: 25)
  --cache.snapshot value              Percentage of cache memory allowance to use for snapshot caching (default = 10% full mode, 20% archive mode) (default: 10)
  --cache.noprefetch                  Disable heuristic state prefetch during block import (less CPU and disk IO, more time waiting for data)

ACCOUNT OPTIONS:
  --unlock value                      Comma separated list of accounts to unlock
  --password value                    Password file to use for non-interactive password input
  --signer value                      External signer (url or path to ipc file)
  --allow-insecure-unlock             Allow insecure account unlocking when account-related RPCs are exposed by http

API AND CONSOLE OPTIONS:
  --ipcdisable                        Disable the IPC-RPC server
  --ipcpath value                     Filename for IPC socket/pipe within the datadir (explicit paths escape it)
  --http                              Enable the HTTP-RPC server
  --http.addr value                   HTTP-RPC server listening interface (default: "localhost")
  --http.port value                   HTTP-RPC server listening port (default: 8545)
  --http.api value                    API's offered over the HTTP-RPC interface
  --http.corsdomain value             Comma separated list of domains from which to accept cross origin requests (browser enforced)
  --http.vhosts value                 Comma separated list of virtual hostnames from which to accept requests (server enforced). Accepts '*' wildcard. (default: "localhost")
  --ws                                Enable the WS-RPC server
  --ws.addr value                     WS-RPC server listening interface (default: "localhost")
  --ws.port value                     WS-RPC server listening port (default: 8546)
  --ws.api value                      API's offered over the WS-RPC interface
  --ws.origins value                  Origins from which to accept websockets requests
  --graphql                           Enable GraphQL on the HTTP-RPC server. Note that GraphQL can only be started if an HTTP server is started as well.
  --graphql.corsdomain value          Comma separated list of domains from which to accept cross origin requests (browser enforced)
  --graphql.vhosts value              Comma separated list of virtual hostnames from which to accept requests (server enforced). Accepts '*' wildcard. (default: "localhost")
  --rpc.gascap value                  Sets a cap on gas that can be used in eth_call/estimateGas (0=infinite) (default: 25000000)
  --rpc.txfeecap value                Sets a cap on transaction fee (in ether) that can be sent via the RPC APIs (0 = no cap) (default: 1)
  --jspath loadScript                 JavaScript root path for loadScript (default: ".")
  --exec value                        Execute JavaScript statement
  --preload value                     Comma separated list of JavaScript files to preload into the console

NETWORKING OPTIONS:
  --bootnodes value                   Comma separated enode URLs for P2P discovery bootstrap
  --bootnodesv4 value                 Comma separated enode URLs for P2P v4 discovery bootstrap (light server, full nodes) (deprecated, use --bootnodes)
  --bootnodesv5 value                 Comma separated enode URLs for P2P v5 discovery bootstrap (light server, light nodes) (deprecated, use --bootnodes)
  --discovery.dns value               Sets DNS discovery entry points (use "" to disable DNS)
  --port value                        Network listening port (default: 30303)
  --maxpeers value                    Maximum number of network peers (network disabled if set to 0) (default: 50)
  --maxpendpeers value                Maximum number of pending connection attempts (defaults used if set to 0) (default: 0)
  --nat value                         NAT port mapping mechanism (any|none|upnp|pmp|extip:<IP>) (default: "any")
  --nodiscover                        Disables the peer discovery mechanism (manual peer addition)
  --v5disc                            Enables the experimental RLPx V5 (Topic Discovery) mechanism
  --netrestrict value                 Restricts network communication to the given IP networks (CIDR masks)
  --nodekey value                     P2P node key file
  --nodekeyhex value                  P2P node key as hex (for testing)

MINER OPTIONS:
  --mine                              Enable mining
  --miner.threads value               Number of CPU threads to use for mining (default: 0)
  --miner.notify value                Comma separated HTTP URL list to notify of new work packages
  --miner.gasprice value              Minimum gas price for mining a transaction (default: 1000000000)
  --miner.gastarget value             Target gas floor for mined blocks (default: 8000000)
  --miner.gaslimit value              Target gas ceiling for mined blocks (default: 8000000)
  --miner.etherbase value             Public address for block mining rewards (default = first account) (default: "0")
  --miner.extradata value             Block extra data set by the miner (default = client version)
  --miner.recommit value              Time interval to recreate the block being mined (default: 3s)
  --miner.noverify                    Disable remote sealing verification

GAS PRICE ORACLE OPTIONS:
  --gpo.blocks value                  Number of recent blocks to check for gas prices (default: 20)
  --gpo.percentile value              Suggested gas price is the given percentile of a set of recent transaction gas prices (default: 60)

VIRTUAL MACHINE OPTIONS:
  --vmdebug                           Record information useful for VM and contract debugging
  --vm.evm value                      External EVM configuration (default = built-in interpreter)
  --vm.ewasm value                    External ewasm configuration (default = built-in interpreter)

LOGGING AND DEBUGGING OPTIONS:
  --fakepow                           Disables proof-of-work verification
  --nocompaction                      Disables db compaction after import
  --verbosity value                   Logging verbosity: 0=silent, 1=error, 2=warn, 3=info, 4=debug, 5=detail (default: 3)
  --vmodule value                     Per-module verbosity: comma-separated list of <pattern>=<level> (e.g. eth
> acc0=eth.accounts[0]
"0xbcb1ffd102fb09b4ad4558e53f9e06ed720ce7ed"

> acc1=eth.accounts[1]
"0xab9836f46e51fb4e25e3aaa248a441d86595b628"

> amount = web3.toWei(12.345)
"12345000000000000000"

> personal.unlockAccount(acc0)
Unlock account 0xbcb1ffd102fb09b4ad4558e53f9e06ed720ce7ed
Passphrase:
true

> eth.sendTransaction({ from:acc0,to:acc1,value:amount})
"0xd2ee2d8c73bad76e07d0c7d7551ca2dc0ea5ac615cfb627408853d67b1ad1819"

> web3.fromWei(eth.getBalance(acc1))
12.345

> eth.getTransaction("0xd2ee2d8c73bad76e07d0c7d7551ca2dc0ea5ac615cfb627408853d67b1ad1819")
{ 
  blockHash: "0xf35ddb73525baeecb248045908568f752bd9b2fb77f78da0532778219360729f",
  blockNumber: 828,
  from: "0xbcb1ffd102fb09b4ad4558e53f9e06ed720ce7ed",
  gas: 21000,
  gasPrice: 1000000000,
  hash: "0xd2ee2d8c73bad76e07d0c7d7551ca2dc0ea5ac615cfb627408853d67b1ad1819",
  input: "0x",
  nonce: 0,
  r: "0x31ef99aa435375cfc90d33ff25314868586ba8967ff2d0e1bc44a9ac32891b0e",
  s: "0x3655f99471c93ed9894edc0dffdf281fba8b081bc9dbd07dfaa241c5a77ff105",
  to: "0xab9836f46e51fb4e25e3aaa248a441d86595b628",
  transactionIndex: 0,
  v: "0x4594",
  value: 12345000000000000000
}

>eth.getTransactionReceipt("0xd2ee2d8c73bad76e07d0c7d7551ca2dc0ea5ac615cfb627408853d67b1ad1819")
{ 
  blockHash: "0xf35ddb73525baeecb248045908568f752bd9b2fb77f78da0532778219360729f",
  blockNumber: 828,
  contractAddress: null,
  cumulativeGasUsed: 21000,
  from: "0xbcb1ffd102fb09b4ad4558e53f9e06ed720ce7ed",
  gasUsed: 21000,
  logs: [],
  logsBloom: "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
  status: "0x1",
  to: "0xab9836f46e51fb4e25e3aaa248a441d86595b628",
  transactionHash: "0xd2ee2d8c73bad76e07d0c7d7551ca2dc0ea5ac615cfb627408853d67b1ad1819",
  transactionIndex: 0
}
>

我们体验了一次从 account[0] ----> account[1] 转移了 12.345 个ETH 的过程。

通过这两章的练习，我们思考一下：
1、转移的12.345个ETH，区块链将数据保存在哪里。
2、通过这笔转账，我们思考一下 ，一个交易的生命周期。

大家可以将自己的思考，在下面留言，一起交流。

2020年9月10日晚。